"I'll be spending my time this summer and fall doing my job in Congress and visiting with and listening to people in Utah," Matheson told The Daily. "I won't be traveling to North Carolina."

Matheson is running in the most heavily Republican district of any Democrat in the House — the newly drawn district would have given President Obama just 41 percent of its vote in 2008. He's routinely broken with his party, voting against their healthcare reforms as well as climate change legislation, though he's said he'll vote for Obama in the fall.

Matheson is facing a tough reelection race in a district that is two thirds new to him against Mia Love, the African-American mayor of a small Utah town who many national GOP operatives predict is a rising star.

He's the seventh Democratic officeholder to say he won't attend the convention. Others include West Virginia Gov. Earl Ray Tomblin (D), Sen. Joe Manhin (D-W.Va.), and Reps. Nick RahallNick Joe RahallWe shouldn't allow politics to impede disaster relief Break the cycle of partisanship with infant, child health care programs Clinton mulls role in 2018 midterms MORE (D-W.Va.), Mark Critz (D-Pa.), Kathy Hochul (D-N.Y.) and Bill Owens (D-N.Y.).